Abstract: Materials to be tested for resistance of immersion swelling, drying shrinkage, thermal expansion and thermal contraction under light exposure are placed on a mount on a rotating shaft which immerses the sample in water, heats and dries it, and exposes it to light before cooling it by again immersing it in water. The samples may be simultaneously exposed to air pollutants by adding gases to a corrosion resistant chamber enclosing the rotating shaft. The chamber enclosing the rotating samples is composed of a lower tank base and a cover fitting into a liquid seal well on the tank base. The cover is fitted with fluorescent lights, an infrared heating strip, a thermocouple and a viewing port. A controller with indicator for the radiant heating strip and a speed control on the rotating shaft drive motor together with "run" and "pause" controls permit selection of the exposure cycles and their conditions.